Question

In a species, the weight of newborn ranges form 2 to 5 kg. 97% of the newborn with an average weight between 3 to 3.3 kg survive whereas 99% of the infants born with weights from 2 to 2.5 or 4.5 to 5 kg die. Which type of selection process is taking place?

• A. Cyclical selection
• B. Directional selection
• C. Stabilising selection
• D. Disruptive selection

Answer 1

The correct option is C Stabilising selection

Natural selection is of 3 types :

1. Stabilisation : more individuals acquire mean character value
2. Directional change : more individuals acquire one of the extreme values
3. Disruption : more individuals acquire peripheral character value at both ends of the distribution curve

Here, as most newborns with average weight survive, it is a stabilising selection.